Step 3:Place below javascript method in the aspx page or you can place it in .js file and include it in the page.
showdiv method will be called on mouse over of div.
showdivonClick will be invoked on click of dropdownlist.
getSelectedItem will be called on click of checkbox and anchor.
check will be call on any click on the page basically it is used to hide the div on click of any where on the page apart from div.